This grant application proposes a 5-year training program to launch an academic career of an independent cardiovascular physiologist and a clinical anesthesiologist. In July 2002, the principal investigator completed residency training in the Department of Anesthesiology and Critical Care Medicine at the Johns Hopkins University and a research fellowship in the Department of Medicine, Division of Cardiology, The Institute of Molecular Cardiobiology, supervised by Brian O'Rourke, Ph.D., and Eduardo Marban, M.D., Ph.D. This unique interdepartmental training with abundant intellectual and physical resources honed the applicant's creative, scientific and clinical skills. This proposal integrates mitochondrial physiology with a clinically significant problem (ischemia-reperfusion injury) using a novel platform technology (multi-photon imaging of an intact heart). Drs. O'Rourke and Marban will mentor the principal investigator. Dr. Marban is Director of the Institute of Cardiobiology, with a well-established record of training successful cardiac physiologists. Dr. O'Rourke is Director of The Johns Hopkins University Imaging Facility and a leader in cardiac mitochondrial physiology. In addition, an advisory committee of highly successful, senior anesthesiologists, physician-scientists will provide scientific and career guidance. The project will focus on intracellular and intercellular physiology of mitochondrial during ischemia and reperfusion. Recent work in the O'Rourke lab demonstrated mitochondrial membrane potential oscillations in isolated cardiomyocytes and the key role of mitochondrial KATP channels in cardio- protection. The proposed experiments will examine mitochondrial physiology in the intact heart. The specific aims are: 1) Developing multi-photon confocal microscopy as a platform technology to examine intracellular and intercellular events in the intact heart, 2) Evaluating possible mechanisms of mitochondrial ATP-sensitive potassium channels in cardioprotection in an intact heart, 3) Describe mitochondrial membrane potential oscillations in the intact heart and relate these findings to reactive oxygen species generation. This novel project will examine sub-cellular, cellular, and multi-cellular mitochondrial physiological phenomena in an intact heart.